Abstract: A method for producing a calcium phosphate-based material comprising:(a) molding a calcium phosphate powder;(b) preliminarily calcining the resulting molding in a vacuum or under a reduced pressure until the relative density is 95% or more; and(c) firing the molding in air, an inert gas, or nitrogen gas.

Abstract: A calcium-phosphate type hydroxyapatite for chromatographic separation is in the form of spherulites having a mean particle diameter of 0.5 to 50 .mu.m, preferably 1 to 10 .mu.m. The spherulites are each an aggregate mainly of acicular crystallites belonging to a series of hexagonal systems and having unit lattice constants of 9.58.+-.0.08 .ANG. for the a axis and 7.00.+-.0.05 .ANG. for the c axis. The hydroxyapatite is produced by granulating a calcium-phosphate type hydroxyapatite in the form of a gel and then firing the granular apatite at 400.degree. to 700.degree. C., preferably at 500.degree. to 600.degree. C. The firing is performed by heating the granules in the presence of oxygen or air for a given period of time.

Abstract: A bone prosthetic material composed of calcium phosphate group granules which have open cells with an average pore size of 0.01-(10 .mu.m).sup.2 over a surface density of at least one per 10 .mu.m.sup.2. The prosthetic material is prepared by mixing organic inflammable particles with a calcium based powder, granulating and then firing the mixture.

Abstract: Column packing materials useful in applications such as liquid chromatography, as well as a process for producing such a packing material are described. A first aspect of the invention concerns a column packing material composed of a spherical substrate having a coating of a calcium phosphate based compound on the surface thereof.A second aspect of the invention concerns a packing material comprising porous calcium phosphate based granules having open pores with an average pore size of from 0.01 to 20 .mu.m, said granules being composed of crystalline particles with an average size of from 0.1 to 10 .mu.m.A third aspect of the invention concerns a spherical packing material for liquid chromatography comprising spherical particles of at least one material selected from the group consisting of Ca.sub.10 (PO.sub.4).sub.6 (OH).sub.2, Ca.sub.3 (PO.sub.4).sub.2, Ca.sub.2 P.sub.2 O.sub.7, Ca(PO.sub.3).sub.2, Ca.sub.10 (PO.sub.4).sub.6 F.sub.2 and Ca.sub.10 (PO.sub.4).sub.6 Cl.sub.

Abstract: A porous ceramics material produced by the process comprising the steps of (i) mixing two or more ceramics in such a manner that at least one of the ceramics is different in sinterability from the others and is mixed in an amount of from 1 to 99 wt % based on the total amount of the ceramics; and (ii) sintering thus obtained mixture; a packing for chromatography comprising the porous ceramics material; and a process for producing the porous ceramics material.

Abstract: A process for producing calcium phosphate ceramics having a porous surface is described, which comprise the steps of:a) preparing untreated calcium phosphate ceramics, which comprises a mixture of hydroxyapatite and tricalcium phosphate, andb) treating said untreated ceramics with an acidic solution to selectively dissolve the tricalcium phosphate in the surface of the ceramics.

Abstract: A method for producing a calcium phosphate-based material comprising:(a) molding a calcium phosphate powder;(b) preliminarily calcining the resulting molding in a vacuum or under a reduced pressure until the relative density is 95% or more; and(c) firing the molding in air, an inert gas, or nitrogen gas.

Abstract: A .beta..sub.2 microglobulin adsorbent composed of hydroxyapatite particles having an average size of 5 to 2,000 .mu.m is disclosed. The adsorbent preferably has a Ca/P ratio of 1.5 to 1.8.

Abstract: A calcium-phosphate type hydroxyapatite for chromatographic separation is in the form of spherulites having a mean particle diameter of 0.5 to 50 .mu.m, preferably 1 to 10 .mu.m. The spherulites are each an aggregate mainly of acicular crystallites belonging to a series of hexagonal systems and having unit lattice constants of 9.58.+-.0.08 .ANG. for the a axis and 7.00.+-.0.05 .ANG. for the c axis. The hydroxyapatite is produced by granulating a calcium-phosphate type hydroxyapatite in the form of a gel and then firing the granular apatite at 400.degree. to 700.degree. C., preferably at 500.degree. to 600.degree. C. The firing is performed by heating the granules in the presence of oxygen or air for a given period of time.

Abstract: A PPI radar apparatus is constructed such that even when a transmission time cycle of radio waves is varied by switchover of a distance range to any of short, middle and long distance ranges, a sweep display time cycle of a radar video signal received in any of the distance ranges is maintained constant at all times; the sweep display time cycle is determined to meet the middle distance ranges, in the short distance ranges in which the reception time of radio waves is short, the video signals are written in storage means in real-time and then displayed by readout of the video signals at a low speed in synchronism with the sweep time cycle, in the long distance ranges in which the reception time of radio waves is long, the video signals are written in storage means in real-time and then displayed by a number of readouts in one sweep display time cycle; and the video signals written in a plurality of storage means are parallelly read out and a mean value or peak of the read-out video signals is obtained by arit

Abstract: A sweep termination generating circuit adopts an octagon boundary for sweep termination which is set by combining a plurality of comparators so as to be circumscribed about the display screen of a circular CRT. When the sweep position is deviated from the center of the display screen for the purpose of displaying a radar image by PPI sweep, the circuit allows the comparators to detect that a scanning signal for scanning an electron beam from the off-center sweep position has reached the boundary for sweep termination and thereby generates a sweep termination signal.

Abstract: A PPI display apparatus allows a radar image or bearing marker to be displayed on a circular CRT screen through sweeping on the basis of a plan position indicator system. In the apparatus, the generation of a radar antenna angle signal, generation of a bearing angle signal representing the angle of a bearing cursor, generation of an antenna angle signal corrected by adding a deflection angle to the antenna angle, and generation of sine and cosine signals corresponding to the antenna angle or bearing angle are all carried out through digital processing.